O'Donnell will join co-hosts Charlie Rose and Gayle King on "CBS This Morning" in the fall. Hill, who was a co-anchor of the previous incarnation of CBS' morning program, "The Early Show," is in discussions regarding a new role.

"This is a very exciting development for our morning program and for all of CBS News," CBS News Chairman Jeff Fager said in a statement. "Norah is an accomplished reporter with all the skills for the job. She's a hard worker who knows her story and, as she has shown time after time at the White House, she can think on her feet on live television."

O'Donnell served as a fill-in host on the program last week. She's been with CBS News for a year.

Despite the changes made in the last year, "CBS This Morning" is still third in the morning-show ratings, behind "Today" and "Good Morning America," which have been fiercely competing for the No. 1 spot.

Late last month, "Today" co-anchor Ann Curry announced that she was vacating her spot on the show after weeks of speculation. Similarly to Hill, she negotiated a role as an anchor at large and roaming national and international correspondent. She returned to the show last weekend to co-anchor coverage of the aftermath of the Aurora, Colo., shootings, alongside her replacement, Savannah Guthrie.